g0] is estimated from the solution pressure
reading at [P.
s] is the nucleated solution pressure entering the die slit, [P.
The first case accounts for the fact that gas diffuses into the cells as the solution pressure decreases such that cell growth during the die flow is driven by both the gas pressure in the cells and the diffusion of gas into the cells.
The design parameters chosen to satisfy these requirements are the nucleated solution pressure during shaping, [P.
g], is a function of the solution pressure surrounding the cells, P, and the surface energy, [[Gamma].
As the solution pressure
drops further, the system will either nucleate additional microcells and expand the existing cells by gas diffusion or only expand the existing cells.